This invention relates to techniques and apparatus for achieving ablation of tissue through the use of focussed ultrasound. It is disclosed in the context of a system and method for the ablation of prostate tissue in the treatment of, for example, benign prostate hyperplasia (BPH), but is believed to be applicable to the treatment of other conditions as well.
The use of transrectally applied high intensity focussed ultrasound in the treatment of diseases of the prostate is well documented. There are, for example, the disclosures of U.S. Pat. Nos. 5,117,832 and 5,676,692 and Fry, F. J. et al, xe2x80x9cUltrasound and Microbubbles: Their Generation, Detection and Potential Utilization in Tissue and Organ Therapyxe2x80x94Experimental,xe2x80x9d Ultrasound in Med. and Biol., vol. 21, no. 9, pp. 1227-1237, 1995 and Sanghvi, N. T., et al, xe2x80x9cNoninvasive Surgery of Prostate Tissue by High-Intensity Focused Ultrasound,xe2x80x9d IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 43, no. 6, pp. 1099-1110, November 1996. U.S. Pat. Nos. 5,409,006 and 5,443,069 also disclose the application of ultrasound for the treatment of BPH. Several references disclose the treatment of BPH by electromagnetic radiation, for example, microwaves, applied transrectally, transurethrally or otherwise. Illustrative of these references are U.S. Pat. Nos.: 5,330,518 and 5,480,417. Other ultrasound applications for the treatment of disease are illustrated in, for example, U.S. Pat. Nos. 5,247,935; 5,219,401; 5,215,680; 5,149,319; 5,054,470; 5,036,855; 4,955,365; 4,951,653; 4,858,613; 4,658,828; 4,586,512; and, 4,620,546. The disclosures of these references are incorporated herein by reference.
Although the prostate can effectively be treated transrectally, urologists are trained in the transurethral treatment of the prostate. As a result, there has been some resistance to transrectal treatment of the prostate. The present invention is disclosed in the context of transurethral treatment of the prostate.
According to one aspect of the invention, a method for treating tissue includes orienting an ultrasound transducer at a first longitudinal orientation and a first angular orientation adjacent a treatment region, exciting the transducer to ablate tissue adjacent the first longitudinal orientation and the first angular orientation within the treatment region, orienting the transducer at the first longitudinal orientation and a second angular orientation adjacent the treatment region, exciting the transducer to ablate tissue adjacent the first longitudinal orientation and the second angular orientation within the treatment region, orienting the transducer at a second longitudinal orientation and the first angular orientation adjacent the treatment region, and exciting the transducer to ablate tissue adjacent the second longitudinal orientation and the first angular orientation within the treatment region.
According to another aspect of the invention, a method of treating tissue comprises orienting an ultrasound transducer at a first longitudinal orientation and a first angular orientation adjacent the treatment region, exciting the transducer to ablate tissue adjacent the first longitudinal orientation and the first angular orientation within the treatment region, orienting the transducer at a second longitudinal orientation and a second angular orientation adjacent the treatment region, and exciting the transducer to ablate tissue adjacent the second longitudinal orientation and the second angular orientation within the treatment region.
Illustratively according to these aspects of the invention, orienting the transducer at a first longitudinal orientation and a first angular orientation includes positioning a catheter including a lumen adjacent the treatment region, maintaining substantially the position of the catheter adjacent the treatment region, and passing the transducer into the lumen so that the transducer is oriented adjacent the treatment region.
Further illustratively according to these aspects of the invention, the method includes providing an indicator for indicating the longitudinal and angular orientation of the transducer.
Further illustratively according to these aspects of the invention, the method includes providing a drive system for driving the transducer, providing the transducer and providing the drive system together including providing an ultrasound transducer and drive system having a variable focal length.
Additionally illustratively according to these aspects of the invention, positioning a catheter adjacent the treatment region includes positioning a catheter including a balloon region adjacent the treatment region and filling the balloon region to maintain substantially the position of the catheter adjacent the treatment region.
According to another aspect of the invention, an apparatus for treating tissue includes an ultrasound transducer for orienting at a first longitudinal orientation and a first angular orientation adjacent a treatment region, for orienting at the first longitudinal orientation and a second angular orientation adjacent the treatment region, and for orienting at a second longitudinal orientation and the first angular orientation adjacent the treatment region, and a drive system for exciting the transducer to ablate tissue adjacent the first longitudinal orientation and the first angular orientation within the treatment region, adjacent the first longitudinal orientation and the second angular orientation within the treatment region, and adjacent the second longitudinal orientation and the first angular orientation within the treatment region, respectively.
According to another aspect of the invention, an apparatus for treating tissue includes an ultrasound transducer for orienting at a first longitudinal orientation and a first angular orientation adjacent a treatment region, and for orienting at a second longitudinal orientation and a second angular orientation adjacent the treatment region, and a drive system for exciting the transducer to ablate tissue adjacent the first longitudinal orientation and the first angular orientation within the treatment region, and adjacent the second longitudinal orientation and the second angular orientation within the treatment region.
Illustratively according to these aspects of the invention, the apparatus further includes a catheter including a lumen for positioning adjacent the treatment region, the lumen permitting passage of the transducer into the lumen so that the transducer can be oriented adjacent the treatment region.
Further illustratively according to these aspects of the invention, the apparatus includes an indicator for indicating the longitudinal and angular orientation of the transducer.
Additionally illustratively according to these aspects of the invention, the transducer and the drive system together include a transducer and drive system having a variable focal length.
Illustratively according to these aspects of the invention, the catheter includes a balloon region adjacent the treatment region, filling the balloon region maintaining substantially the position of the catheter.